Tiered Wedding Cake

AHi - first time on here but could really do with some advice please! I've been making cakes for a while now and I like the more unusual cakes, however, I'm being brave or stupid and making my own wedding cake. I sat tonight and drew it out and I know what I want but having not attempted a cake like this before there's some things I'm slightly dubious/terrified about! I will be doing a trial run but just wanted a bit if advice on....:

I'm making 4 tiers, a chocolate, a fruit, a regular sponge and a carrot cake. It will be decorated in sugar paste roses aside from the bottom layer which will be a fruit cake with a rose based design along the bottom of the cake which is covered in white fondant. When I've made roses before I've attached them to fondant but I wondered if anyone had to a buttercream cake and to what success? I could do fondant on the sponge cake fine, but I don't know about the carrot and chocolate cake, unless I use chocolate fondant which I'm not to keen in. A good chocolate, probably white buttercream would taste much better in my opinion as would a cream cheese buttercream on the carrot cake. Has anyone attempted this and do you think you could do two fondant two buttercream or will it just look a mess? Or does anyone have any ideas that could help at all?! If you've made a cake with sugarpaste decorations attached to a buttercream cake or have any advice on icings that would be a huge help! It's not until may but after Christmas I want yo get practicing so I'm happy with what I'm doing and to avoid any last minute cake runs to marks and Spencer's! Thanks!

You are brave, but the trial run will be super helpful! I think if you do 2 fondant and 2 buttercream just stack the 2 fondant together and the 2 buttercream on top. Others on this site will be able to guide you better, though.

I put fondant , on chocolate cake and carrot cake . I make a white choc ganache infused with orange and chai for the carrot and choc ganache on the choc cake. I would cover them all in fondant , but then again I hate buttercream and refuse to do it.

ASo you would cover them in ganache and then just a normal fondant, then attach the flowers. I don't really like buttercream, I fund it quite sickly and much prefer ganache. It's ok in a red velvet cake but in a chocolate cake you want something much more decadent

AAwesome, thanks for your advice. That sound lovely infusing it with those flavours, I love chai! What would you normally do with transporting a tiered cake? As it's my own it would be way easier to fully assembly it at home but I'm worried about it getting damaged taking it to the venue. Ideally I would like to take it fully assembled to the venue the day before as it is a restaurant so I know it's in good hands!